Novel ionic mixed-ligands complexes of the types cis- and trans-[Pt(amine) 2 (pm) 2 ](NO 3 ) 2 (where pm=pyrimidine) were synthesized and studied in the solid state by IR spectroscopy and in aqueous solution by multinuclear ( 195 Pt, 1 H and 13 C) magnetic resonance spectroscopy. The results of the solution NMR characterization have shown that the isolated compounds are pure. In 195 Pt NMR, the cis RNH 2 complexes were observed at slightly lower fields (ave. −2441ppm) than the equivalent trans analogues (ave. −2448ppm). For Me 2 NH, the difference between the two isomers is larger (29ppm). The complexes are observed at lower fields (difference of 100ppm) than the corresponding [Pt(amine) 4 ] 2+ complexes, which might indicate the presence of π-backdonation in the Pt–pm bond. In 1 H NMR, the coupling constants 3 J( 195 Pt– 1 H amine ) are larger in the cis compounds (38–48Hz) than in the trans analogues (30–36Hz). The 3 J( 195 Pt– 1 H pm ) values are also larger for the cis isomers. In 13 C NMR spectroscopy, the coupling constants 3 J( 195 Pt– 13 C amine ) are 36Hz (ave.) for the cis complexes and 26Hz (ave.) for the trans isomers, while the 2 J( 195 Pt– 13 C amine ) are 18Hz (cis) and 14Hz (trans), respectively. The 3 J( 195 Pt– 13 C 5(pm) ) values are 36Hz (cis) and 28Hz (trans). A few 2 J( 195 Pt– 13 C pm ) couplings were observed (7–10Hz).